U.S. Pat. No. 5,599,164 issued to Murray describes a centrifugal pump with a booster or secondary impeller. The centrifugal pump assembly and a method of using same described in the '164 patent includes a vertical or horizontal overhung housing assembly having a primary inlet, a primary discharge, a secondary inlet and a secondary discharge. A shaft is in spaced relationship within the overhung housing assembly. A single primary impeller is mounted on the shaft for receiving fluid from the primary inlet and discharging fluid through the primary discharge. A booster or secondary impeller is mounted on the shaft proximate the primary impeller for receiving fluid from the secondary inlet and discharging fluid through the secondary discharge. All fluid introduced to the secondary inlet originates from the primary discharge. The fluid in the secondary inlet flows through the booster impeller and discharges through the secondary discharge. The secondary discharge is separate from the primary discharge.
Generally, the pump in the '164 patent requires that the primary discharge connection to the secondary inlet is made using a separate conduit. There exists a need for a simpler, more robust pump having primary and secondary impellers each discharging to a separate outlet.